A billion is a number with two distinct definitions:

  •  1,000,000,000, i.e., one thousand million, or 109 (ten to the ninth power), as defined on the short scale. This is now the meaning in all English dialects.
  • 1,000,000,000,000, i.e., one million million, or 1012 (ten to the twelfth power), as defined on the long scale. This is one thousand times larger than the short scale billion, and this number is now normally referred to as one trillion.

Number Multiples

In mathematics, natural numbers are those used for counting and ordering.

Some authors begin the natural numbers with 0, corresponding to the non-negative integers 0, 1, 2, 3, and others start with 1, corresponding to the positive integers 1, 2, 3, etc...

Properties of the natural numbers, such as divisibility and the distribution of prime numbers, are studied in number theory. Problems concerning counting and ordering, such as partitioning and enumerations, are studied in combinatorics.